1. Field of the Invention
This invention relates to a data backup method for having a data storage apparatus back up data stored in a data processing apparatus by transferring them via a communications link and to the data processing apparatus using the data backup method.
2. Description of the Related Arts
An increase in the processing capabilities of a data processing apparatus has produced an increase in a data volume processed by one or more data processing apparatuses and thus an increase in importance of a data backup. Especially, a system comprising a plurality of data processing apparatuses connected to a network may cause the entire network to shut down, unless data lost due to a fault in the data processing apparatus or the network are restored expeditiously. Thus, a network provides a data storage apparatus for backing up the newest data to be retrieved immediately after a data loss due to a fault, thereby preventing a system from shutting down.
To ensure the newest data are stored at all times for an expeditious retrieval, such a system connected to a network requires a data storage apparatus to store update data transferred from a data processing apparatus via a communications link. However, a data transfer from a data processing apparatus to a data storage apparatus upon every data change causes data backup times to occupy a large portion of an available window of a communications link, which is disadvantageous as evidenced by a lowered efficiency in utilizing a communications link.